The crystal structure of the silver complex Ag(CH3CN)(2)[CO(C2B9H11)(2)] has been determined and features trigonal bipyramidal Ag(I) with B-H...Ag interactions comprising the trigonal plane. When the host molecule cyclotriveratrylene (CTV) is combined with silver(I) cobalt(III) bis(dicarbollide), different supramolecular assemblies with various Ag(I) coordination environments result, depending on the crystallization conditions used. The complex Ag(CH3CN)(H2O)(CTV)(2)[Co(C2B9H11)(2)] has tetrahedral Ag(l) with coordination interactions with water, acetonitrile, and CTV through Ag-C bonds, and the structure features bis(CTV) capsules. The complexes Ag(CH3CN)(3)(CTV)-[Co(C2B9H11)(2)](CH3CN)(0.5) and Ag(CH3CN)(4)(CTV)[Co(C2B9H11)(2)](CH3CN)(0.25) both have [Ag(CH3CN)(n)](+) complex cations forming host-guest interactions with the CTV. In the former case, three CH3CN ligands bind to Ag(I) and there are further weak Ag-O coordinate interactions to the CTV, whereas the latter features the more usual tetrahedral [Ag(CH3CN)(4)](+). Complexes with CTV show host-guest interactions with coordinated acetonitrile guests.